Warbird Escort Fighters were introduced to assist in the capital ship defence role. While Paragons were extremely effective in the role, they couldn't just be the only vessel suited for the role. Fighters are decent up to a point, but vessels with multi-directional weapons systems are considered to be perfect for escorts.
The Warbirds first saw action over Mars. A squadron of 8 fighters were sent to deal with insurrectionist forces. This engagement proved that these ships were not just for the escort role. Unfortunately, they were extremely popular with insurrectionist forces, and so a large number of warbirds never saw friendly action.

Disruptors have only been introduced along with the Warbirds as an experimental weapon system. Essentially, a particle beam is used along with plasma to create the beam. As the particle beam is of opposite charge to the plasma, the latter is attracted to the beam, and so disruptors came into existence.
The weapon is capable of inflicting hull damage and can overload electronic equipment due to the ionic charges of the 2 constituents of the weapon.

Solid rocket boosters are a necessity for ground based Warbirds as they are unable to lift off due to their un-aerodynamic structure. This is the reason for such a high ground launch speed.

End notes:
This one sprung to mind at some point a few weeks ago. While it's by no means my best fighter, it's still, in my opinion, a fairly decent model. I'll leave you to decide for yourselves.